Pi is a mathematical value, approximately equal to 3.14 3.14 . This is the commonly used approximation for calculations.

Pi is symbolized by π π .

Examples of some mathematical expressions include π π :

P=2×R×π P_○=2\times R\timesπ

A=π×R×R A_○=π\times R\times R

Pi approximately equal to 3.14

Practice Pi

Examples with solutions for Pi

Exercise #1

M is the center of the circle.

Perhaps AB=CD AB=CD

MMMAAABBBCCCDDDEEEFFFGGGHHH

Video Solution

Step-by-Step Solution

CD is a diameter, since it passes through the center of the circle, meaning it is the longest segment in the circle.

AB does not pass through the center of the circle and is not a diameter, therefore it is necessarily shorter.

Therefore:

ABCD AB\ne CD

Answer

No

Exercise #2

There are only 4 radii in a circle.

Step-by-Step Solution

A radius is a straight line that connects the center of the circle with a point on the circle itself.

Therefore, the answer is incorrect, as there are infinite radii.

Answer

False

Exercise #3

Which diagram shows a circle with a point marked in the circle and not on the circle?

Step-by-Step Solution

The interpretation of "in a circle" is inside the circle.

In diagrams a'-d' the point is on the circle, and in diagram c' the point is outside the circle.

Answer

Exercise #4

Which figure shows the radius of a circle?

Step-by-Step Solution

It is a straight line connecting the center of the circle to a point located on the circle itself.

Therefore, the diagram that fits the definition is c.

In diagram a, the line does not pass through the center, and in diagram b, it is a diameter.

Answer

Exercise #5

Is it possible that the circumference of a circle is 8 meters and its diameter is 4 meters?

Video Solution

Step-by-Step Solution

To calculate, we will use the formula:

P2r=π \frac{P}{2r}=\pi

Pi is the ratio between the circumference of the circle and the diameter of the circle.

The diameter is equal to 2 radii.

Let's substitute the given data into the formula:

84=π \frac{8}{4}=\pi

2π 2\ne\pi

Therefore, this situation is not possible.

Answer

Impossible

Exercise #6

In which of the circles is the center of the circle marked?

Video Solution

Answer

Exercise #7

Is there sufficient data to determine that

GH=AB GH=AB

MMMAAABBBCCCDDDEEEFFFGGGHHH

Video Solution

Answer

No

Exercise #8

M is the center of the circle.

In the figure we observe 3 diameters?

MMMAAABBBCCCDDDEEEFFFGGGHHH

Video Solution

Answer

No

Exercise #9

M is the center of the circle.

Perhaps MF=MC MF=MC

MMMAAABBBCCCDDDEEEFFFGGGHHH

Video Solution

Answer

Yes

Exercise #10

Fill in the corresponding sign

π?3.147 \pi?3.147

Video Solution

Answer

= =

Exercise #11

Fill in the corresponding sign

π?3.2 \pi?3.2

Video Solution

Answer

<

Exercise #12

Is it possible for a circle to have a circumference of 314.159 meters (approximately) and a diameter of 100 meters?

Video Solution

Answer

No.

Exercise #13

Is it possible for the circumference of a circle to be 10π 10\pi if its diameter is 2π 2\pi meters?

Video Solution

Answer

No.

Exercise #14

Is it possible for the circumference of a circle to be 5π 5\pi meters if its diameter 5 meters?

Video Solution

Answer

No.

Exercise #15

Is it possible that a circle with a circumference of 50.6 meters has a diameter of 29 meters?

Video Solution

Answer

No.

Topics learned in later sections

  1. Circle
  2. Diameter
  3. The Circumference of a Circle
  4. The Center of a Circle
  5. Radius
  6. How is the radius calculated using its circumference?
  7. Perimeter
  8. Area
  9. Elements of the circumference
  10. Area of a circle